Portable electronic devices usable outdoors generally have a built-in rechargeable battery. The charging of this rechargeable battery is performed indoors by connecting a power connector to the housing, or by placing the electronic device in a desktop holder for charging. FIG. 1A illustrates an example of a portable electronic device 10 that is charged by being placed in a desktop holder 1 for charging. The electronic device 10 is, for example, a cell-phone 10, and the electronic device and the cell-phone are hereinafter given the same sign 10.
The desktop holder 1 has a recess 2 that receives the lower end part 10L of the cell-phone 10. Holding protrusions 3 for locking the lower end part 10L of the cell-phone 10 inserted into the recess 2 and charging pins 4 are protruded into the recess 2. The holding protrusions 3 and the charging pins 4 are biased by springs (not shown) so as to protrude into the recess 2. Therefore, when the lower end part 10L of the cell-phone 10 is inserted into the recess 2, the holding protrusions 3 and the charging pins 4 are pressed by the lower end part 10L and are retracted from the recess 2 into the desktop holder 1. A connector 8 for supplying power from an AC adapter (not shown) to the charging pins 4 of the desktop holder 1 is connected to the back of the desktop holder 1.
The cell-phone 10 that is charged by inserting the lower end part 10L thereof into the desktop holder 1 is waterproof, and an elastic member for waterproofing is attached to a part that is sandwiched between a lower housing 11 and an upper housing 12 of the cell-phone 10 and that blocks intrusion of moisture and dust. The elastic member for waterproofing will be described later. The lower housing 11 of the cell-phone 10 is provided with a camera 5 and a fingerprint sensor 6, and charging terminals 21 are exposed on the lower end part 10L thereof. The camera 5 and the fingerprint sensor 6 are independently waterproofed.
When, in a portable electronic device, charging terminals are exposed on the lower end part of the electronic device, metal plates having a U-shaped cross-section are used as discussed in Japanese Laid-open Patent Publication No. 2011-248825. The metal plates having a U-shaped cross-section have an exposed portion exposed on the lower end part, a first extended portion perpendicular to the exposed portion, and a second extended portion adjacent to the first extended portion and parallel to the exposed portion. The second extended portion is connected to a charging circuit of the electronic device.
The charging terminals 21 in the example illustrated in FIG. 1A are provided in a charging terminal holder 20 that is a separate member from the lower housing 11, illustrated in FIGS. 1B and 1C. The charging terminals 21 are visible through openings 10W provided in the lower housing. The charging terminal holder 20 has an oval cylindrical main body 22. An O-ring 23 for waterproofing is attached around the side thereof. Two charging terminals 21 are exposed on the top thereof. Two connection terminals 25 for connection to a circuit board built in the cell-phone and two mounting holes 26 are provided on and in the bottom thereof. The two charging terminals 21 and the two connection terminals 25 are connected to each other inside the main body 22. Claws 27 are provided on the lower part of the side of the charging terminal holder 20 in the longitudinal direction. The claws 27 are for positioning of the charging terminal holder 20, and are not indispensable.
FIG. 2A illustrates an example of the structure of the lower end part of a circuit board 14 built in the cell-phone 10. At the lower end of the circuit board 14, two spring contacts 15 are mounted at positions corresponding to the connection terminals 25 illustrated in FIG. 1C. FIG. 2B is a side view illustrating the structure of the spring contacts 15 mounted on the circuit board 14.
FIG. 2C is an enlargement of a section of the lower part of the cell-phone 10 illustrated in FIG. 1A. Mounting pins 17 provided on a mount 16 mounted at the lower end of the circuit board 14 are inserted into mounting holes 26 provided in the bottom of the charging terminal holder 20, and the charging terminal holder 20 is thereby attached to the circuit board 14. In this state, the O-ring 23 for waterproofing attached to the side of the charging terminal holder 20 is in close contact with a frame member 13 inside the upper housing 12 so that moisture and dust do not intrude into the frame member 13. The charging terminals 21 on the top of the charging terminal holder 20 are connected by connection portions 28 inside the main body 22 to connection terminals 25 on the bottom of the charging terminal holder 20. The connection terminals 25 are connected by the spring contacts 15 to a circuit on the circuit board 14. In the electronic device having charging terminals in the comparative art, charging terminals have to be provided separately from the housing. This increases the number of components, increases the assembling man-hour for connecting the charging terminals to the circuit board inside the device, and therefore increases the cost. In addition, a space for mounting members for connecting the charging terminals exposed to the outside of the housing and the circuit board inside the device has to be left inside the housing, and it is difficult to reduce the thickness of the electronic device.
These arts are disclosed, for example, in Japanese Laid-open Patent Publication No. 2011-248825.